Distribution of corneal densitometry in different grades of keratoconus

Purpose: To evaluate the use of Scheimpflug tomography in corneal densitometry (CD) in comparing the stages of keratoconic eyes. Methods: Keratoconic (KC) corneas (stages 1–3 classified according to the topographic parameters) were examined using the Scheimpflug tomographer (Pentacam, Oculus) using the CD software. CD was measured over three different depths (anterior stromal layer [120 ?m], posterior stromal layer [60 ?m], and middle stromal layer between these two layers), and concentric annular zones (0.0 to 2.0, 2.0 to 6.0, 6.0 to 10.0, and 10.0 to 12.0 mm diameter area). Results: The study participants were divided into three groups: keratoconus (KC) stage 1 (KC1) with 64 participants, keratoconus stage 2 (KC2) with 29 participants, and keratoconus stage 3 (KC3) with 36 participants. Comparing CD of all three layers (anterior, central, and posterior) of the cornea over different circular annuli (0–2, 2–6, 6–10, and 10–12 mm) revealed a significant difference in the 6–10 mm annulus between all groups and in all layers (P = 0.3, 0.2, and 0.2, respectively). Area under curve (AUC) was done. It revealed that the central layer showed the highest specificity (93.8%) in comparing KC1 and KC2, whereas CD in the anterior layer between KC2 and KC3 had the highest specificity (86.2%). Conclusion: CD showed increased values in the anterior corneal layer and in the annulus 6–10 mm more than other locations in all stages of KC

Corneal densitometry in patients with arcus senilis and its correlation with serum lipid levels

Purpose: To evaluate corneal densitometry (CD) of patients with arcus senilis (AS) and its association with the serum lipid markers. Methods: This is a cross?sectional, case?control study. The AS diagnosis was made clinically. Forty?five eyes of 45 patients with AS and 38 eyes of 38 age?matched control subjects with no noticeable AS were enrolled in the study. All participants underwent detailed ophthalmologic examination along with corneal Scheimpflug imaging with CD measurement. The evaluated serum lipid markers of the participants included total cholesterol, triglyceride, low?density lipoprotein (LDL), high?density lipoprotein (HDL), and very?low?density lipoprotein (VLDL). The Spearman correlation analysis was used to correlate the serum lipid values and the CD. P < 0.05 was defined as statistically significant. Results: The male to female ratio was 26/19 and 14/24 in the study and control groups, respectively (P = 0.057). The mean age was 59.56 ± 8.7 and 56.47 ± 8.6 years in the study and control groups, respectively (P = 0.117). The mean total CD values in the zones extending from 2 to 12 mm were higher in the study group than in the control group (P < 0.001). The serum HDL level was found to be significantly decreased in the study group compared to the control group (P = 0.048 and Z = ?1.976). There was a significant positive correlation between the serum triglyceride level and the CD value of the outermost zone (10–12 mm) (r = 0.334 and P = 0.025). Conclusion: The CD of patients with AS was found to increase not only in the peripheral zone but also in the cornea’s paracentral zone compared to the healthy controls. The serum triglyceride level should give an insight into the intensity of arcus senilis. The serum HDL levels were decreased in patients with AS

Novel technique of sutureless glueless intrascleral fixation of single-piece intraocular lens / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To explore single centre results of sutureless intrascleral fixation of single-piece posterior chamber intraocular lens(IOL).<p>METHODS: In this prospective study, 50 aphakia cases were evaluated. Preoperative and postoperative visual acuity, slit lamp and fundus examination, applanation tonometry, keratometry, IOL MASTER measurement, optical coherence tomography(OCT), Scheimpflug imaging were done for an extensive evaluation.<p>RESULTS: All IOLs were successfully implanted at the desired position without intraoperative complications. Postoperative complications included corneal edema(<i>n</i>=2), raised intraocular pressure(IOP)(<i>n</i>=3), cystoid macular edema(CME)(<i>n</i>=1)and decentration(<i>n</i>=2). All were managed to the level of good visual recovery. Surgery videos were retrospectively evaluated in cases of postoperative complications. There was no significant change in corneal astigmatism.<p>CONCLUSION: After extensive 6mo follow up with evaluation of a variety of parameters, our technique of sutureless, glueless scleral fixation of IOL using single-piece IOL has shown favorable results and a potential option in visual rehabilitation.

Evaluation of Scheimpflug imaging system as an added tool in improving the accuracy of reference marking (as compared to the slit lamp marking system) for toric intraocular lens implantation

Purpose: To assess the role of Scheimpflug imaging in improving the accuracy of reference marking for toric IOL implantation. Methods: In this prospective, randomized, clinical trial all patients with cataract and pre-existing significant regular corneal astigmatism, who required implantation of a toric IOL were included in the study, and patients with any ocular pathology or abnormality were excluded. Patients were divided into two groups: For one group of patients, Group I (GI), reference marking was finalized using slit lamp only, and for the second group, Group II (GII), after slit lamp marking, the reference marks were checked using Goniometer of Scheimpflug imaging. The primary outcome was to determine the axis of toric intraocular lens (IOL) postoperatively (within 1 hour) and compare it with the desired axis of placement. Results: We found a statistically significant difference in the two groups (P < 0.001) suggesting Group II (4 step technique) is better than Group I (3 step technique). Conclusion: Scheimpflug imaging, an extra step preoperatively, is an effective measure to reduce errors in reference marking and thereby improving the refractive outcome of toric intraocular lens.

Corneal densitometry and its correlation with anterior and posterior elevation in keratoconus / 国际眼科杂志(Guoji Yanke Zazhi)

· AIM:To evaluate the corneal densitometry in treatmentnaive patients with keratoconus and its relevance with anterior and posterior corneal elevation.· METHODS:Keratoconic corneas were examined using the Pentacam.Corneal densitometry was measured over a 12-mm diameter area,divided by annular concentric zones and depths,more over anterior and posterior corneal elevation was measured.Keratoconus was classified according to the topographic keratoconus classification.· RESULTS:A total of 152 subjects [72 patients with keratoconus (46 male,26 female) and 80 healthy control subjects (50 male,30 female)] were included in the study.There were significant differences in corneal densitometry values of the groups in central 2 mm keratoconus (KC)=19.62±4.17 gray scale unit (GSU),N=15.38±1.54 GSU(P＜0.0001),and in annulus of 2 to 6 mmin diameter (K=16.40±2.18 GSU,N=15.31±1.25 GSU,P＜0.0001).When densitometry values for different depths were examined,the anterior layer presented the highest value (KC =23.69±3.71 GSU,N =20.91 ±2.52 GSU,P＜0.0001),which was significantly higher than the values obtained in the central and posterior layer (KC =14.34± 1.70 GSU,N=13.61±1.21 GSU,P=0.001 and KC=11.40± 1.23 GSU,N =12.35±0.88,P=0.002 respectively).Analysis of the correlation between corneal densitometry for each layer depth (anterior,central and posterior) with posterior corneal elevation values demonstrated significant association (r =0.293,r =0.278 and r =0.294 respectively).The similar correlation was not found between corneal densitometry for each layer depth and anterior corneal elevation (r=-0.211,r=-0.101,r=0.99 respectively).In the control patients such a significant correlation between posterior/anterior corneal elevation and corneal light backscatter for each layer depth was not found.· CONCLUSION:The densitometry map reveals that light backscatter was higher in the central portion of the anterior keratoconic cornea.Corneal densitometry values of keratoconus patients were correlated with posterior corneal elevation in 0-2,6-10 and 10-12 annuli and in all anterior,central and posterior layers.The densitometry level was higher in more advanced stages.

Corneal backscatter in insulin-dependent and non-insulin-dependent diabetes mellitus patients: a pilot study / Retroespalhamento luminoso das córneas de pacientes com diabete melito dependente e não dependente de insulina: estudo piloto

ABSTRACT Purpose: To compare central corneal backscatter obtained from Scheimpflug images between patients with insulin-dependent and non-insulin-dependent diabetes mellitus (IDDM and NIDDM, respectively) and healthy controls. Methods: Seven patients with IDDM (7 eyes), eleven patients with NIDDM (11 eyes), and sixteen healthy subjects (16 eyes) were included in this pilot study. Scheimpflug imaging system (Pentacam, Oculus Inc., Germany) was used to obtain optical sections of the cornea. Seven meridians were analyzed for each eye, oriented from 70° to 110°. Optical density values for the central 3-mm and 5-mm zones of the cornea were obtained by image analysis using external software. Results: Corneal backscatter was significantly higher in the diabetic patients than in the controls for the central 3-mm (p=0.016) and 5-mm (p=0.014) zones. No significant differences in corneal backscatter were found between the IDDM and NIDDM groups for either zone (both p>0.05). In the NIDDM group, significant correlations were observed for both central zones between corneal backscatter and age (3 mm: r=0.604, p=0.025; 5 mm: r=0.614, p=0.022) and central corneal thickness (3 mm: r=0.641, p=0.017; 5 mm: r=0.671, p=0.012); this was not found in the IDDM group (p>0.05). The presence of diabetes showed a significant effect on central corneal backscatter (Kruskal-Wallis test, p<0.001). Conclusions: Diabetic patients showed higher values of corneal light backscatter than healthy subjects. Corneal optical density analysis may be a useful tool for monitoring and assessing the ocular changes caused by diabetes.

RESUMO Objetivo: Determinar os valores de retroespalhamento luminoso central da córnea em pacientes diabéticos dependentes (IDDM) e não dependentes (NIDDM) de insulina, comparados com controles saudáveis, a partir de imagens de Scheimpflug. Métodos: Foram incluídos neste estudo piloto sete pacientes com IDDM (7 olhos), onze pacientes com NIDDM (11 olhos) e dezesseis indivíduos saudáveis (16 olhos). O sistema de Scheimpflug (Pentacam, Oculus Inc. Germany) foi utilizado para obter secções ópticas da córnea. Foram analisados sete meridianos para cada olho, orientados de 70º a 110º. A análise de imagem por meio de software externo permitiu a obtenção de valores da densidade óptica para os 3 e 5 mm centrais da córnea. Resultados: O retroespalhamento luminoso corneano foi significativamente maior em pacientes diabéticos para os 3 mm centrais (p=0,016) e para os 5 mm centrais (p=0,014) em relação ao grupo controle. Não foram encontradas diferenças significativas entre os grupos IDDM e NIDDM para cada zona analisada (p>0,05 em ambos os casos). No grupo NIDDM, observaram-se correlações significativas para as zonas centrais de 3 mm e 5 mm, entre retroespalhamento luminoso corneano e idade (r=0,604 p=0,025 e r=0,614 p=0,022, respectivamente) e espessura central corneana (r=0,641 p=0,017; r=0,671 p=0,012, respectivamente), o que não foi encontrado no grupo IDDM (p>0,05). O teste de Kruskall-Wallis indicou que a presença de diabete tem um efeito significativo sobre a retroespalhamento central da córnea (p<0,001). Conclusões: Pacientes diabéticos apresentaram valores mais elevados de retroespalhamento luminoso corneano do que indivíduos saudáveis. A análise da densidade óptica corneana pode ser uma ferramenta útil para monitorar e avaliar as alterações oculares causadas pela diabete.

Comparison of Ultrasound and Scheimpflug Methods for Central Corneal Thickness.

Aim: The central corneal thickness (CCT) of healthy individuals was measured with an ultrasonic pachymeter (UP) and the Scheimpflug imaging system (SIS) and the results were compared to evaluate the agreement between the two methods in this study. Materials and Methods: The 61 subjects who had no ocular pathology or systemic disease except blepharitis were included in the study. CCT measurements of all subjects were performed with the UP (Sonomed 300P Pacscan) and SIS (Nidek Optical biometer AL-Scan) devices and the results were compared. The t test and the Bland-Altman plot were used as the statistical methods. Results: The study sample consisted of 61 cases including 20 males and 41 females. The mean age was 41.8±12.4 (20-58) years for the males and 46.2±9 (24-60) years for the females with no statistically significant difference (P=0.116). The mean CCT measurement of all the 61 subjects was 544.5±31 μm in the right eyes and 547.3±33 μm in the left eyes with UP, 530.7±27.6 μm in the right eyes and 531.6±25.5 μm in the left eyes with SIS. The CCT in the SIS results was an average of 13.8 μm thinner than the UP results in the right eye, 15.7 μm in the left eye and this difference was statistically significant (p=0.001 in right and left eyes). A high degree of agreement was found between the two methods with the Bland-Altman plot. Conclusion: A high degree of agreement was found between SIS and UP regarding CCT measurements and the mean SIS results were 13.8 μm and 15.7 μm thinner than the UP results in the right eyes and left eyes respectively.

The Relationship between the Nuclear Density Using Scheimpflug Imaging with Phacoemulsification Parameters

PURPOSE: To evaluate the correlation between nuclear density measured using the Pentacam(R) (Oculus Optikgerate GmbH, Wetzlar, Germany) Scheimpflug imaging system and phacoemulsification parameters. METHODS: The nuclear density was measured using maximal nuclear density with ImageJ, Pentacam(R) nucleus staging (PNS), average value and maximal value in lens densitometry. Intraoperatively, effective phaco time (EPT) and balanced salt solution (BSS) used were noted and compared with the nuclear density calculation methods. As an index of corneal endothelial cells, the changes in cell density (CD) were compared with the nuclear density. RESULTS: Regarding EPT, maximal nuclear density with ImageJ (r = 0.379, p < 0.01) and PNS (r = 0.367, p < 0.01) were correlated positively, but the other methods were not correlated. Concerning BSS used, maximal nuclear density with ImageJ (r = 0.279, p = 0.03) and PNS (r = 0.286, p = 0.04) were positively correlated, but the other methods were not correlated. The specular microscopy showed that as the nuclear density increased, the postoperative CD tended to decrease, but without statistical significance. CONCLUSIONS: Preoperative nuclear density measurements using maximal nuclear density with ImageJ or PNS were correlated with phacoemulsification parameters.

Relationship between lens density measurements by Pentacam Scheimpflug imaging and torsional phacoemulsification parameters / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the relationship between the density values of the lens nucleus measured using Pentacam Scheimpflug imaging and torsional phacoemulsification dynamics such as the level of ultrasound energy, as well as the duration and amount of fluid used in patients with age-related nuclear cataract. METHODS: This was a prospective observer-masked study. Pentacam Scheimpflug imaging was performed following pupil dilation. The cataracts were automatically graded from 1 to 5 using pentacam nucleus densitometry (PND), also known as Pentacam nucleus staging (PNS) software by the same observer. After phacoemulsification, total Ultrasound ( U/S ) time, Cumulative dissipated energy ( CDE ) , Torsional U/S time, and Estimated fluid use were automatically calculated and displayed on the monitor of Infiniti OZiL IP phacoemulsification system. One-way analysis of variance ( ANOVA ) was used to assess differences between groups. The Tamhane test was used for multiple group analysis. Spearman correlation analysis was used to assess the relationship between lens density measured by PND and the dynamics of torsional phacoemulsification. P RESULTS:In the present study, 125 eyes from 125 patients were evaluated. Mean age was 69. 7 ± 9. 4y (range: 48 - 88y), and 61 men and 64 women were included. The highest and lowest values of U/S total time, torsional U/S time, CDE, and Estimated fluid use were 0. 70 - 158. 90s, 0. 70-158. 50s, 0. 11-42. 65, and 21-98 mL in groups, respectively. Significant differences were found among PND groups. When the relationship between phacoemulsification dynamics and PND values were evaluated, there were significant correlations between PND value and total ultrasound time (r=0. 767;P CONCLUSION:An objective degree of nucleus density obtained by PND scoring before cataract surgery may allow antecedent determination of intraoperative phacoemulsification parameters. Thus, individualized phacoemulsification parameters should be developed for each patient. This will lead to the use of a smaller amount of phacoemulsification energy, resulting in decreased in endothelial cell loss, quicker and better visual healing, and less steroid use.

Scheimpflug imaging for keratoconus and ectatic disease.

Scheimpflug cross-sectioning anterior segment imaging offers significant advantages over traditional placido based curvature analysis and ultrasound pachymetry. The accurate measurement of both the anterior and posterior corneal surfaces and the anterior and posterior lens allows for the creation of a three-dimensional reconstruction of the anterior segment. Changes on both the posterior cornea and/or corneal thickness map are earlier indicators of ectatic change than would otherwise be identifiable with only anterior curvature and ultrasonic pachymetry. Scheimpflug imaging also covers significantly more of the cornea than was possible with placido based devices. This added coverage is critical in the proper diagnosis of peripheral diseases such as pellucid marginal degeneration (PMD).

Scheimpflug imaging in anterior megalophthalmos.

We report an anterior megalophthalmos case with decreased corneal thickness and show the findings using Scheimpflug imaging. A 25-year-old male was diagnosed with anterior megalophthalmos. In both eyes, enlarged corneal length was measured. Beside a comparatively good visual acuity, a thin but clear cornea, a fairly deep anterior chamber, and central lens opacity were found. Scheimpflug images were taken using Pentacam HR. Scheimpflug-based imaging can provide us new data at the examination of this syndrome affecting the whole anterior segment.